Why ccl4 is inert to water

So, it can react with H2O. Secondly, CCl4 has zero dipole moment where as SiCl4 has not. Carbon doesn't contain d orbital in its valence shell to accept lone pair electrons Whereas silicone element which belongs same group has d orbital to accept lone pair electrons So sicl4 can dissolve in H2O than CCl4. That is an easiest explanation. Reason behind the above is because Si has greater atomic radius than C Also, carbon does not have low-lying empty d-orbital to get the electrons from water.

Another explanation. The four chlorine atoms shield the small carbon atom from the water molecule, serving as a steric hindrance while silicon do not get shielded by chlorine. But in the case of a carbon atom, that isn't possible. The silicon atom is bigger, and so there is more room around it for the water molecule to attack, and the transition state will be less cluttered.

But silicon has the additional advantage that there are empty 3d orbitals available to accept a lone pair from the water molecule. Carbon doesn't have 2d orbitals because there are no such things. There are no empty 2-level orbitals available in the carbon case. This means that the oxygen can bond to the silicon before the need to break a silicon-chlorine bond.

This makes the whole process energetically easier. Liquid SiCl 4 fumes in moist air for this reason - it is reacting with water vapour in the air. The reaction of lead IV chloride with water is just like the silicon tetrachloride one. You will get lead IV oxide produced as a brown solid and fumes of hydrogen chloride given off.

This will also, of course, be confused by the decomposition of the lead IV chloride to give lead II chloride and chlorine gas - see above.

Ask Question. Asked 6 years, 2 months ago. Active 1 year, 8 months ago. Viewed 16k times. Improve this question. Gaurang Tandon 8, 10 10 gold badges 55 55 silver badges bronze badges. Abmon98 Abmon98 1 1 gold badge 6 6 silver badges 17 17 bronze badges. Add a comment. Active Oldest Votes. Improve this answer. An unstable transition state indicates a high activation energy for the reaction.

The other problem is that there is no appropriate empty carbon orbital the oxygen lone pair can occupy. If it attaches before the chlorine starts to break away, there would be an advantage. Forming a bond releases energy, and that energy would be readily available for breaking a carbon-chlorine bond.

In the case of a carbon atom, however, this is impossible. The situation is different with silicon tetrachloride. Silicon is larger, so there is more room for the water molecule to attack; the transition is less cluttered.

Silicon has an additional advantage: there are empty 3d orbitals available to accept a lone pair from the water molecule. Carbon lacks this advantage because there are no empty 2-level orbitals available. The oxygen atom can therefore bond to silicon before a silicon-chlorine bond breaks, makes the whole process easier energetically.